WinHTTrack Website Copier is free software under the GNU GPL, version 3 or
later. See license.txt for the terms.

The complete corresponding source for this exact build:

  Windows interface  https://github.com/xroche/httrack-windows/tree/98a513d76febc77f6e81a187cbbf07a2df149439
  Engine             https://github.com/xroche/httrack/tree/46294200ed7b8098ce3f16ac50586897f9c045e5
  coucal (in engine) https://github.com/xroche/coucal/tree/93ec411c55667050965c7bb8826c22adc3521dec

Downloadable archives of those revisions. coucal has to be taken separately:
it is a submodule, so the engine archive carries an empty src/coucal.

  https://github.com/xroche/httrack-windows/archive/98a513d76febc77f6e81a187cbbf07a2df149439.tar.gz
  https://github.com/xroche/httrack/archive/46294200ed7b8098ce3f16ac50586897f9c045e5.tar.gz
  https://github.com/xroche/coucal/archive/93ec411c55667050965c7bb8826c22adc3521dec.tar.gz